Polymers such as those prepared from methacrylate-butadiene-styrene ("MBS") monomers and polymers predominantly based on acrylic and methacrylic-"(meth)acrylic"- esters monomers, are routinely employed as additives in polymeric matrices to provide products with improved impact properties. MBS polymers, however, are prone to thermal and oxidative degradation at elevated temperatures. (Meth)acrylic polymers, herein termed acrylic impact modifiers ("AIMS"), are prone to thermal and oxidative degradation, although to a lesser degree than MBS polymers. This tendency of MBS and AIMS polymers to degrade at elevated temperatures reduces the ability of these polymers to impart improved impact strength in polymer matrices of acrylics, polyamides, and other engineering resins, as well as in blends which require relatively high processing temperatures.
MBS and AIMS polymers employed as additives in polymeric matrices are routinely treated with stabilizers to protect them against thermal and oxidative degradation. However, these stabilizers may cause polymers to lose impact strength and develop colored impurities in the polymer matrix as a byproduct of their antioxidant action.
A need therefore exists to improve stabilizers for polymers such as MBS and AIMS and to improve polymeric products that employ the polymers which incorporate these improved stabilizers.